Circuit breaker



June'9, 1942. w. H. FRANK ETAL C IRGUI T BREAKER Original Filed Jan. 17, 1936 2 Sheets-Sheet 1 TORNEYS.

June 9, 1942. w H. FRANK r 2,285,770

CIRCUIT BREAKER Original Filed Jan. 17, 1936 2 Sheets-Sheet 2 Patented June 9, 1942 UNITED'STATES PATENT OFFICE 2,285,770 CIRCUIT Barman William R. Frank and Joseph A. Messing, Detroit, Mich, assignors to Bulldog Electric Products Company, Detroit, Mich a corporation of West Virginia Continuation or application sci-n1 No. 59,031, January 1'1, 1936. This application September 14, 1939, Serial No. 294,808

17 Claims.

switch "01! (Fig. 4) and overload "oil" (Fig. 5).

The device includes a-base l0 having a pair of contacts II which are to be butt pressure en-- gaged by the contacts l2 on the ends of a resilient bridging contact arm it. One of the contacts H is connected to the line, and the other is connected to one leg of the thermostatic or bimetallic warping element I4, the other Leg of the latter being connected to the load. When the contact arm i2 is in on" position, current flows through contacts Ii and I 2, contact arm I! and warping element I 4.

To the vertically moving contact arm I! is rigidly secured an upwardly projecting sliding link II and a downwardly projecting guide plate I 4, these being insulated from arm l2, as shown.

The lower end of the guide plate It slides between two spring jaws ll of a lower guide block i4 firmly fastened to base 14. The sides of the sliding link It snugly fit into an upper guide I .block ll rigidly secured to a vertical front plate 2|.

A link 22 is pivotally connected at 22 to a horizontal link or arm 24 and is slidably connected to the upper end of link II, through an elongated slot 24 in link Ii, receiving a pin 24 of link 22. A coiled compression resisting spring 21 is mounted on the right hand end of link 24, between a pin 22 thereon and the bight of a U- shaped, horizontally positioned spring compression link 24, which is pivotally connected at 2| to a pawl 42, the latter being pivotally connected by shouldered screws 24 on its left hand end to front plate 2| and vertical back plate 48a. As indicated, the link 24 passes through a slot in the bight of link 2!, and these links -move as a unit, around pivot 2|. In the "on" position. the right hand or free end I! of pawl 22 is held down by a tongue 24 of warping ele ment i4.

The left hand end U of link 24 is pivotally connected to an operating bell crank 24 by a pin is, the latter sliding in an arcuate slot u of the crank. The bell crank has an extension 42 forming an operating handle for the device,

- and is pivotally supported on the cross shaft 42.

the latter connecting front plate 2I and the vertical back plate 420.

The parts just described may beoperated as a simple, quick make and break switch as follows:

Assume the parts to be in on" position (Fig. 2). Whenthe handle 42 is moved to the right, the bell crank 24 rotates clockwise, carrying end 21 0! link 24 along with it, thus moving links 24 and 29, together about the pivot 3i, clockwise This action pulls link 24 to the left a slight degree and builds up an increased compression in coil spring 21. All this while, the link 22 and its pin 24 travels the length of the slot 25 in sliding link II, and link I! and arm I! do not move, linkv ll being held by spring jaws II frictionally eng ing guide part It. As soon as link 24 has passed ot'er center (shaft 42) the coil "spring operates, to move links 24 and 20 further past shaft 42, with a snap action, thus pulling contact arm l2 to its o'fl" position, for a quick break of the circuit,

slot 4| permitting snap action movement of links to the 011" position, and permits the operator to free the contacts l2 in case they should stick,

and to move the switch positively to: the of!- position, independently of the spring, in the event.

the spring should becomebroken or weakened too much to function of its'own accord.

The bell crank 24 may be moved to the extl'eme -o position as limited by the engagement of the reset lug 44 and stop 45 on pawl 32.

Reverse movement of handle 42, to the left, from the oil" position (Fig. 4) imparts a conn ter-clockwise movement to link 24 about pin 21. This action pulls link 24 to the left and compresses spring 21 between pin 24 and the blght of the spring compression link 2l, until link 24 is past center (shaft 42) link It and arm l4 do not move,beinghe1d by spring clips l'l frlctionally engaging guide part pin 28 travels I4. Then the compressive force of the spring reto link 24, forcing down link 22, sliding link I5, and arm l3, until the circuit isv completed .through contacts II and I2.

Slot 4| permits a snap action movement of links 24 and 29, independent of the movement of handle 42, in order to effect a quick make, independent of the operator. The bell crank may be moved to the extreme on position, as determined by the length of the slot 4|, and the on position of link 24, as shown in Fig. 2.

The action just described is a quick make action, and takes place when spring 21 functions roperly. At other times, the positiveconnection between handle 42 and link I5, as previously described, insures contact making.

During switch operation, travel of pawl 32, about its pivot screws 33 is prevented, by its end 35 being held by the tongue 36 of warping element |4.

It will be observed that slot 4| provides a lost motion connection between handle 42 and link 24, which permit movement of the latter, when overcenter and as influenced by spring 21, independently of the handle for accelerating the quick make and break action of the linkage 24, 22, I5, etc., the extent of this action being determined by the dimensions of slot 4| and the associated parts. A positive make and break action of the linkage is, however, assured by the positive (even though lost motion) connection between handle 42 and link 24.

The foregoing parts, in com'unctionwith other parts to be described below, serve to move contact arm from on position'to a second or overload "oiI position, when element |4 warps to the right due to an overload in the line, and also serve to enable the operator to reset the switch after it had been tripped on overload, by moving the various parts, linkages, and the pawl 32 from their overload "ofi position to their normal off position without causing contact arm H to close the circuitand these operations are carried on as follows: v

Assume the switch to be in- "on" position.

acts, giving a rapid counter-clockwise movement By properly proportioning and connecting the parts, the action may be such that during movement of the handle 42, lug 44 can be resetting link 32 to its normal latched position, during the time that link 24 is moving overcenter to the off position.

It will be seen that the position of the con- ,tact arm l3 does not change while the other parts move from overload off position to switch off" position (reset position). Accordingly, there is no danger of the circuit being closed, even momentarily, until the breaker is under the control of the warping element M.

It will be observed at this time that the breaker described in the foregoing possesses certain novel and desirable characteristics. It is tripe free; it operates with a quick make and break action, both on normal switch operations, and on overload; it insures positive make and break, in addition to and without interfering with the quick make and break; and it can be reset after tripping, with a snap action.

In addition, in the event the spring 21 breaks, it will not fall into the live parts of the breaker, with consequent damage, but will remain upon the link 24 upon which it is mounted, being held between pin 28 and link 29.

Further, sincethe spring 21 does not have to be flexed to any great extent, due to the tan- When the element l4 warps (to the right) its tongue 36 releases pawl end 35, permitting the compression in spring 21 to tend to move link 29, and consequently pin 3|, to the left. Since link 29 is fixed to pawl 32 at 3|, the movement of pin 3| to the left is on an arc whose center is pivot 33, and is necessarily accompanied by an upward movement of pin 3|. The parts move up to the point where pawl 32 is engaged by the hooked ledge 41 on stop 48. Such movement causes pin 23 to be pulled upwardly. This move ment, operating through links 22 and I5, raises contact arm I 3 to the position shown in Fig. 5,

known as "overload oil, for breaking the cir: cuitp Quick break is of course assured by the action of spring 21.

, In view of the fact that this action can take place without interference from handle 42, due to the fact that the pivot 39 does not move on this action, the breaker cannot be prevented from tripping, merely by holding handle 42 so that pivot 39 .can not move. In other words, the breaker will trip even though the handle be held. This characteristic places the breaker in the trip-free class. I

When the parts are to be reset, that is to say, when contact arm I3 is to be moved from overload off" (Fig. 5) to switch "012 (Fig. 4) handle 42 is moved to the right, rotating bell crank 38 clockwise until the stop lug 44 on bell crank 38 gentialrelationoi the link 24 and the crank 38, the life of the spring is relatively prolonged.

Further, it is to be noted that this circuit breaker employs only one spring for all its operation, this spring serving to perform t e functions of quick make and quick break under normal switching, and quick break under overload tripping.

Further, since the spring 21 connects the operating link 24 and the pawl, it is free of the handle, and therefore does not interfere with positive make and break action of the handle, as contradistinguished from constructions wherein the spring connects the operating link or part to the handle.

It will be seen that the handle is connected to the pin 39 by means of a positive lost motion connection including the slot 4| in which rides the pin 39, and that this lost motion connection is constant in character, being no diiferent on overload release than on normal operation.

It is also observed that the contact arm is connected by links to the operating mechanism at a point between its anchorage 35 and its anchorage 39 so that movement of link 24 of the operating mechanism about either anchorage as a pivot directly causes movement oi the contact arm |3 with a lost motion connection assured by the pin and slot at 22-26.

These features result in a simple construction wherein actuation of the operating mechanism is reflected with great force in movement of the a,ass,v7o 'eontactpressureatcontacts "-41 because when theparts-areinthe closedcircuitpositimthe spring 21 tends to rotate the operator as a whole radially around the pivot 48 and to the right, lowering the left end oi the operator and moving it to the right and raising the right end of the operator and moving it to the right. This tende'ncy oi the spring is arrested by the contact pressure established at contacts l2--li and by the latch engagement at It.

This spring pressure, when the parts are in the "on" position, imparts a bias to the contact and to the operating unit above described which tends to move those parts to the overload released position oi Fig. 5, such movement taking place only in the event oi a release by the latch.

. Thus in the closed circuit position the spring has three functions. (1) to establish" contact pressure, (2) to establish and maintain latch engagement, and (3) to tend to move. the parts to the position of Fig. 5 in the event of a latch release.

The unit consisting of parts 24, 21, 29 and I2 may be considered as a spring means or as a Conspring operator for the entire breaker. sidering it as a spring means or a spring unit, it will be observed that the unit as a whole has one end connected to the latch and the other end to the handle. The spring alone, namely spring 21,

' is not,'however, properly considered as directly connected to the latch and handle, as is the spring unit, because the connection between the spring and the latch is established through the pawl I2 and the connection between the spring and the handle is established through part 24.

It will here be observed that the breaker here- 0! includes a spring means which is directly connected to the latch and the handle, that spring means consisting of the spring 21 and the links.

established positively through links or the like and not through a spring, the latter providing an operating force but not a connection between the handle and contact. In the instant breaker'the handle is connected by links 24, 22, and II to the movable contact and that connection is a positive connection. Thus movement ointhe handle positively moves the movable contact to open and closed circuit positions regardless of the spring;

Handle movement, however, meanwhile stresses the spring to provide snap action for the last part of each handle actuated movement of the contact.

'It will be observed that unlike previously known breakers the spring hereoi operates to provide a force which tends to hold the parts in either of the two handle actuated positions. For example, in the closed circuit position of Fig. 2

trasts favorably with known breakers wherein cams or the like. are utilised to hold the'partrinthe open circuit position, with springs being utilized to hold the pertain the closed circuit position. the cams being manipulable'to overcome the springs for open circuit movement.

It will also be observed that in the breaker herein disclosed the resetting or relatchi'ng movement or the handle, from the overload released open circuit position oi-I'ig. 5 to the open circuit position of Hg. 4, relatches the spring means or spring operator without moving the contact to the closed circuit position. Thus it is impossible for the contact to be moved to the closed circuit position without its becoming controlled by the latch which can release and permit the parts to be moved by the spring to the open circuit position free of the handle.

'It will alsobe observed that the spring means or spring operator as a whole pivots on the latch for handle actuation and pivots on the handle for overload release movement and that the contact moves with the spring means" regardless of which end of the spring means is the then anchored end.

It will be observed that in the instant breaker, the interconnection between the movable contact i2 and the operating arm 24 is at a point 23 remote from the axis .39 for the arm 24 and is established directly, rather than, as in the case of the Thomson breaker 01' Patent No. 2,106,580, being at the axis 39 of the arm 24, and established through a normally held latch us, which is released on overload after the main latch is rewith its contact-parts i2, i3, i5, 22, move as a unit, both on manual operation and on overload nection between the handle and the contact is release operation.

We claim:

l. A circuit breaker including a movable contact, a stationary contact, a movable contact operating arm; a handle, and a latch for said arm, and a single spring for biasing the movable contact towards the stationary contact when the and contact move together on all breaker operations, with said latch comprising the sole overload control tor the breaker, the spring being connected to the contact operating arm free and independently oi the handle, and also being operatively connected to the breaker frame, through a pawl which is held directly by the latch and through which the latch holds the arm.

2. A. circuit breaker including a movable contact, a stationary contact, a movable contact operating arm, a handle, and a latch for said am, and a single spring for biasing the movable contact towards the stationary contact when the parts are in circuit closed position, and for biasing the movable contact away from the stationary contact when the arm is released by the the s ring provides a force which tends to hold ton, the movable contact and am being p nected directly, at a point remote from the connection oi the arm to the handle, so that arm the parts therein in their closed circuit position with contact pressure. On the other hand, when the parts are m the position of Fig. '4, the spring provides a force which biases the parts and tends to hold them in the position 0! Fig. 4. This con and contact move together on all breaker operations, with said latch comprising the sole overload control for the breaker, the spring being connected to the contact operating arm free and independently of the handle.

3. A circuit breaker including a movable contact, a stationary contact,-a movable contact operating arm, a handle, and a latch for said arm, and a single spring for biasing the movable contact towards the stationary contact when the parts are in circuit closed position, and for biasing the movable contact away from the stationary contact when the arm is released by the latch, the movable contact and aim being connected directly, at a point remote from the connection of the arm to the handle, so that arm and contact move together on all breaker operations,

with said latch comprising the sole overload control for the breaker, the spring being connected to the contact operating arm free and independently or the handle, and also being operatively connected to the breaker frame. v

d. A circuit breaker including a stationary contact and a movable contact, an operator arm therefor, a latch for pivotally supporting and holding said arm at one point, a handle positively connected to said arm at a second pointfor sup porting and holding it and movable to cause the arm to swing around its latch held point and move the movable contact to and from the stationary contact, a spring biasing the arm to swing around the latch as a fulcrum under the control of the connection between the handle and the arm to cause and maintain contact engagement or to separate the contacts, and to swing around that connection as a fulcrum to move the movable contact and open the circuit in the event of latch release, even though the handle be held, the movable contact and arm being connected directly, at a pointremote from the connection of the arm to the handle, so that arm and contact move together on all breaker operations, with said latch comprising the sole overload control for the breaker.

5. In a circuit breaker, a stationary contact and a movable contact, a movable contact operating arm connected to, and controlling movement of the movable contact to and fromthe stationary contact and thus controlling the engagement of the movable contact with the stationary contact, a latch for said operating arm, spring means for biasing the operating arm in a direction to insure its being held by the latch and the movable contact engaging the stationary contact, a pivotal axis for the operating arm, said axis and said spring means being relatively positioned to provide for rotation of said operating arm about said axis under the influence cf the spring means when released by said latch to move the movable contact to a position separated from the stationary contact, and a handle for moving said axis against said spring means to move the operating arm in a direction to insure the movable contact leaving the stationary contact with the operating arm then being held by the latch, the movable contact and arm being connected directly, at a point remote from the connection of the arm to the handle, so that arm and contact move together on all breaker operations, with said latch comprising the sole overload control for the breaker.

6. In a circuit breaker, a stationary contact and a movable contact, a movable contact operating arm connected to and controlling move tionary contact, a latch for said operating arm,

spring means for biasing thev operating arm in a direction to insure its being held by the latch and the movable contact engaging the stationary contact, a pivotal axis for the movable contact operating arm, said axis and said spring means being relatively positioned to provide for rotation of said operating arm about said axis under the influence of the spring means when released by said latch to move the movable contact to a position separated from the stationary contact, and a handle for moving said axis against said spring means to move the operating arm in a direction to insure the movable contact leaving the stationary contact with the operating arm then being held by the latch, the movable contact and arm being connected directly, at a point remote from the connection of the arm to the handle, so that arm and contact move together on all breaker operations, with said latch comprising the sole overload control for the breaker, and for moving said operating arm into latching engagement with the latch after an automatic move-;

ment of the'operating arm causing contact separation, whereby to relatch the operating arm by the latch.

7. A construction of the character described in claim 5 wherein the handle is separate from and independent of the spring means, eachproviding a force on the operating arm independent of the other.

8. A, construction of the character described in claim 5 wherein the axis and the latch are near ends of the operating arm, and the connection between the latter and the movable contact is between the axis and the latch,

9. A circuit breaker including a movable contact, a stationary contact, a movable contact operating arm, a handle, and a latch for said arm, the handle and movable contact being so connected that movement of the handle in one direction causes the movable contact ,to withdraw from the stationary contact, and inovement of the handle in the opposite direction causes the movable contact to approachthe stationary contact, and a single overcenter spring for biasing the movable contact towards the stationary contact when the parts are in circuit closed position, and for biasing the movable contact away from the stationary contact when the arm is released by the latch, and for causing snap movement of the movable contact to its resting points in on and off positions, the spring being connected to the contact operating arm free and independently of the handle, the'movable contactand arm being connected directly, at a point remote from the connection of the arm to the handle, so that arm and contact move together on all breaker operations, with said latch comprising the sole overload control for the breaker. 10. A circuit breaker including a movable con tact, a stationary contact, a movable contact operating arm, a handle, and a latch for said arm, the handle and movablev contact being so ,connected that movement of the handle in one direction causes the movable contact to withdraw from the stationary contact, and movement of the. handle in the opposite direction causes the movable contact to approach the stationary contact, and a single spring for biasing the movable contact towards the stationary contact when the parts are in circuit closed position, and for biasing the movable contact away from the stationary contact when the arm is released by the latch, and for causing movementof; the movable contact to its resting points in"on" and otl'v aaomvo positions, the spring being connected tothe conations, with said latch comprising the sole overload control ior the breaker.

11. In a circuit breaker, a stationary contact,

a movable contact, a spring means connected to the movable contact and arranged to bias it towards the stationary contact when the spring means is in normal stressed position, a latch di-.

rectly connected to the spring means for holding it under stress in normal contact biasing position. a rotatably mounted handle connected to the spring means and manipulable by rotary movement out of its normal position to stress the spring means and move it bodily out of its normal position and towards the center of rotation 01' the handle so that when the handle is released after such movement the spring means will tend to relieve itself of its stress with a snap action, the relative arrangement of the parts being such that on such stress relieving movementof the spring means following such handle movement and subsequent release, the spring mean will move bodily beyond the center oi rotationiai' the handle and about the connection between the spring means and latch as a pivot, to move the movable contact away from the stationary contact, and also being such that on release oi' the latch, when the handle and spring means are in normal position, the spring means will tend to relieve itself of its stress with a snap action. and in so doing will move bodily about its connection to the handle as a pivot and move the movable contact away from the stationary contact, the movable contact and arm being connected directly, at a point remote from the connection or the arm to the handle, so that arm and contact move together on all breaker operations, with said latch comprising the sole overload control ior the breaker.

12. In a circuit breaker, a stationary contact, a movable contact, a spring means connected to the movable contact and arranged to bias it towards the stationary contact when the spring means is in normal stressed position, a latch directly connected to the spring means for holding it under stress in normal contact biasing position, a rotatably mounted handle connected to the spring means and manipulable by rotary movement out of its normal position to stress the spring means and move it bodily out of its-normalposition and towards the'center of rotation of the handle so that when the handle is released after such movement the spring means will tend to relieve itself of its stress with a snap action,

the relative arrangement of the parts being such that on such stress relieving movement of the spring means following such handle movement and subsequent release, the spring means will move bodily beyond the center of rotation of the handle and about the connection between the spring means and latch as a pivot, to move the movable contact away i'romthe stationary contact, and'also being such that on release of the latch, when the handle and spring means are in normal position, the spring means will tend 5 nected directly, at a point remote from the connection or the arm to the handle, so that arm and contaotmove together on all breaker joperations, with said latch comprising the sole-overlo'ad control for the breaker, the spring means consisting of a spring and links which connect the spring to the latch and handle.

13. A circuit breaker including a movable contact. a stationary contact, a movable contact operating arm, a handle. and a latch for said arm, the handle and movable contact being so connected that movement of the handle in one dito relieve itseli. 01' its stress with a snap action and in so doing will move bodily about its connection to the handle as a pivot and move the movable contact away from the stationary contact, the movable contact and arm being conrection causes the movable contact to withdraw from the stationary contact, and movement of the handle in the opposite direction causes the movable contact to approach the stationary contact, and a single overcenter spring for biasing the movable contact towards the stationary contact when the parts are in circuit closed position, and for biasing the movable contact away from the stationary contact when the arm is released by the latch, and for causing snap movement oi the movable contact to its resting point in 011" position, the spring being connected to the arm tree and independently or the'handle, the movable contact and arm being connected directly, at a point remote from the connection 01' the arm to the handle, so that arm and contact move together on all breaker operations, with said latch comprising the sole overload control tor the breaker.

14. In a circuit breaker, a movable contact, a controlling arm therefor having a pivot point about which it is normally movable, a handle connected to said arm for moving it about said pivot point to the open and to the closed circuit position with asnap action, and support means for said pivot point on said arm. includinga latch operable upon overload to release and allow gether on all breaker operations, with said latch comprising the sole overload control for the breaker.

15. A circuit breaker comprising fixed and movable contacts, a handle for causing movement or said contacts into engagement, a floating actuating arm between said handle and said movable contact, two points about which said arm may pivot, said arm pivoting about one pivot point during manual operation and about the other point during overload operation, spring means between said pivot points urging said arm to rotate about said points, a latch movable in response to overload currents to remove the support of one 01' said pivot points and permit pivoting of said arm'about said other point and thereby carry said movable contact out of engagement with the fixed contact, said movement of the arm in response to overload currents taking place irrespective of the position in which said handle may beheld, and said handle movable to return said am to position where' it is again supported at said point where support was removed, thmovable contact and arm being on all breaker opera 16. A circuit breaker having a stationary contact, a movable contact, an operating arm therefor operatively-connected at one point to a mov-' able contact, a latch for a second point of said arm, a pivotal axis for said arm at a third point thereof remote from the contact and member interconnection point, spring means biasing said member to establish contact and latching engagement when the circuit is closed, said axis and biasing means being relatively positioned to provide for rotation of said arm by said biasing means about said axis when said arm is released by said latch to separate the movable contact from the stationary contact, and a handle for moving said axis against the influence of said biasing means to separate the movable contact from the stationary contact, the movable contact and arm being connected directly, at a point remote from the connection of the arm to the handle, so that arm and contact move together on all breaker operations, with said latch comprising the sole overload control for the breaker.

17. A circuit breaker having a stationary con- 4 tact, a movable contact formed for butt contact therewith, an operating arm therefor operatively connected at one point to the movable contact,

a latch for a second point of said arm, a pivotal contact, and a handle for moving said axis against the influence of said biasing means to.

separate the movable contact from the stationary contact, the movable contact and arm being connected directly, at a point remote from the connection of the arm to the handle, so that arm and contact move together onall breaker operations, with said latch comprising the sole overload control for the breaker.

WILLIAM H. FRANK. JOSEPH A. MESSIN'G;

Disclaimer 2,285,770.-William H. Frank and Joseph A. Messing, Detroit, Mich. CIRCUIT BREAKER. Patent dated June 9, 1942. Disclaimer filed Jan. 15, 1948, by the assignee, Bulldog Electric Products Company.

Hereby enters this disclaimer to claim 2 in said specification.

[Ofiicial Gazette February 17, 1948.]

Disclaimer Messing, Detroit, Mich. CIRCUIT 2,285,770.William H. Frank and Joseph A.

n. 15, 1948, by

BREAKER. Patent dated June 9, 1942. Disclaimer filed Ja the assignee, Bulldog Electric Products Company. Hereby enters this disclaimer to claim 2 in said specification.

[OfiZc u Z Gazette February 17, 1948.] 

